1. Field of the Invention
The present invention relates to data processing systems and more particularly to a method and apparatus for controlling data transfers between first and second information processing elements within a data processing system.
2. Description of the Relevant Art
Data transfers frequently are initiated by a first or a second information processing element, such as a central processing unit (CPU) or an I/O channel, by one information processing element signaling the other that a data transfer is requested. The device which receives the request then signals that it is ready to make the transfer, the transfer occurs, and the requesting device sends an acknowledgment of completion of the transfer. Finally, the device which received the request for transfer acknowledges that its operation is also complete. Although this is an effective serial "handshake" method for controlling the transfer of data between two information processing elements, the sending device must await the acknowledgment from the receiving device before it attempts another transfer. This wastes time, especially when the sending device must perform other tasks and may be busy when the acknowledgment occurs.